Deck 10: T Test for Correlated Groups Samples

Question 1

A correlated-groups t test:

A) compares sample means for two related groups.
B) compares sample means for two unrelated groups.
C) compares standard deviations for two unrelated groups.
D) compares sample means for three or more unrelated groups.

Answer 1

compares sample means for two related groups.

Question 2

After calculating a correlated-groups t test, if you find that it is equal to zero, then:

A) the two means differ significantly.
B) the two means do not differ significantly.
C) there is something wrong in the calculation.
D) none of the above are accurate.

Answer 2

the two means do not differ significantly.

Question 3

If the null hypothesis is true, then the t test should be close to:

A) 0.00.
B) $\pm$ 1.65.
C) $\pm$ 1.96.
D) $\pm$ 3.00.

Answer 3

0.00.

Question 4

If the null hypothesis is not supported, then the t test should be:

A) 0.00.
B) ±1.00.
C) greater than ±1.00.
D) a negative number.

Question 5

Imagine that you conducted a correlated-groups t test with 7 subjects. For a two-tailed test, the t_cv at $\alpha$ = .05 would be:

A) $\pm$ 1.717.
B) $\pm$ 2.447.
C) $\pm$ 1.711.
D) $\pm$ 2.179.

Question 6

If a researcher reported for a correlated-groups t test that t(18) = 2.90, p < .01, how many subjects were there in the study?

A) 18
B) 20
C) 17
D) 19

Question 7

If a researcher reported for a correlated-groups t test that t(12) = 3.66, p < .01, how many subjects were there in the study?

A) 12
B) 14
C) 13
D) 11

Question 8

If a researcher reported for a correlated-groups t test that t(22) = 2.69, p < .01, how many subjects were there in the study?

A) 23
B) 20
C) 22
D) 21

Question 9

If a correlated-groups t test and an independent-groups t test both have df = 16, which experiment used more subjects?

A) Both used the same number of subjects (N = 18).
B) Both used the same number of subjects (N = 17).
C) The correlated-groups t test (N = 17) used more subjects.
D) The independent-groups t test (N = 18) used more subjects.

Question 10

If a correlated-groups t test and an independent-groups t test both have df = 16, how many subjects were in each study?

A) There were 16 subjects in both studies.
B) There were 17 subjects in both studies.
C) There were 17 subjects in the correlated groups and 18 subjects in the independent groups.
D) There were 18 subjects in the correlated groups and 17 subjects in the independent groups.

Question 11

In the formula to compute the correlated-groups t test, the denominator in the equation represents:

A) the standard error of the mean.
B) the estimated standard error of the mean.
C) the standard error of the difference scores.
D) the standard error of the difference between means.

Question 12

A researcher believes exercise reduces anxiety in women. She identifies a group of women who had not exercised before but are now planning to begin exercising. She gives them a 50-item anxiety inventory before they begin exercising and administers it again after six months of exercising. The anxiety inventory is measured on an interval scale and higher numbers indicate higher anxiety. In addition, scores on the inventory are normally distributed. The scores are given below.



-What statistical test should be used to analyze these data?

Question 13

A researcher believes exercise reduces anxiety in women. She identifies a group of women who had not exercised before but are now planning to begin exercising. She gives them a 50-item anxiety inventory before they begin exercising and administers it again after six months of exercising. The anxiety inventory is measured on an interval scale and higher numbers indicate higher anxiety. In addition, scores on the inventory are normally distributed. The scores are given below.



-Identify H₀ and H_a for this study.

Question 14

A researcher believes exercise reduces anxiety in women. She identifies a group of women who had not exercised before but are now planning to begin exercising. She gives them a 50-item anxiety inventory before they begin exercising and administers it again after six months of exercising. The anxiety inventory is measured on an interval scale and higher numbers indicate higher anxiety. In addition, scores on the inventory are normally distributed. The scores are given below.



-Conduct the appropriate analysis.

Question 15

A researcher believes exercise reduces anxiety in women. She identifies a group of women who had not exercised before but are now planning to begin exercising. She gives them a 50-item anxiety inventory before they begin exercising and administers it again after six months of exercising. The anxiety inventory is measured on an interval scale and higher numbers indicate higher anxiety. In addition, scores on the inventory are normally distributed. The scores are given below.



-Should H₀ be rejected? What should the researcher conclude?

Question 16

A researcher believes exercise reduces anxiety in women. She identifies a group of women who had not exercised before but are now planning to begin exercising. She gives them a 50-item anxiety inventory before they begin exercising and administers it again after six months of exercising. The anxiety inventory is measured on an interval scale and higher numbers indicate higher anxiety. In addition, scores on the inventory are normally distributed. The scores are given below.



-If significant, compute the effect size and interpret this.

Question 17

A researcher believes exercise reduces anxiety in women. She identifies a group of women who had not exercised before but are now planning to begin exercising. She gives them a 50-item anxiety inventory before they begin exercising and administers it again after six months of exercising. The anxiety inventory is measured on an interval scale and higher numbers indicate higher anxiety. In addition, scores on the inventory are normally distributed. The scores are given below.



-If significant, draw a graph representing the data.

Question 18

A researcher believes exercise reduces anxiety in women. She identifies a group of women who had not exercised before but are now planning to begin exercising. She gives them a 50-item anxiety inventory before they begin exercising and administers it again after six months of exercising. The anxiety inventory is measured on an interval scale and higher numbers indicate higher anxiety. In addition, scores on the inventory are normally distributed. The scores are given below.



-Calculate the 95% CI.